Controllable pitch propeller



Nov. 5, 1963 H. BLOUNT 3,109,498

CONTROLLABLE PITCH PROPELLER Filed Jan. 12, 1962 3 Sheets-Sheet lINVENTOR.

LUTHER H. BLOUNT BY 6224401 i @144 ATTORNEYS Nov. 5, 1963 1.. H. BLOUNT3,109,498

CONTROLLABLE PITCH PROPELLER Filed Jan. 12, 1962 3 Sheets-Sheet 2 F (5 5INVENTOR.

LUTHER H. BLOUNT BY FIG. 4 flmmw ATTORNEYS 1963 L. H. BLOUNT 3,109,498

CQNTROLLABLE PITCH PROPELLER Filed Jan. 12, 1962 3 Sheets-Sheet 3 BLADECENTER C III! 3/ 38/1 REVERSE Ill FEATHER) 3/ I I l/ I,

MID AHEAD A MAX. THRQW PLUNGER 37/ 7 37, ail 37,,

INVENTOR.

LUTHER H. BLOUNT BY AW ATTORNEYS United States Patent Office lh g/lflPatented Nov. 5, 1963 3,199,498 (ZGNTRQLLABLE llT CH PRGEELLER Luther H.Blount, Warren, RI. (Poppasquash Road, Bristol, RI.) Filed Jan. 12,1962, Ser. No. 165,748 4 Qlainrs. (Cl. fill-160.46)

This invention relates to a controllable pitch propeller.

In a controllable pitch propeller the blades are rotatably mounted inthe hub of the propeller and some means is provided which moves axiallyof the drive shaft and axially of the propeller hub so as to rotate theblades relative to the hub. Various means are utilized for this purpose.

One of the objects of the invention is to provide a mechanicalconnecting means between the rotatable blades and the part which movesaxially of the drive shaft and propeller hub so that the power appliedmay be more advantageously utilized in the shifting of the blades.

Another object of this invention is to provide an arrangement which,while providing the advantageous arrangement of utilizing a maximum ofthe power applied for rotation of the blades, also provides for amovement of the blades angularly about their axes to such an extent thatmovement may occur from the position of reverse through neutral andahead to that of full feathering.

A further object is to utilize a blade and its spindle which may be castin a single piece and the spindle machined to shape and size.

With these and other objects in view, the invention consists of certainnovel features of construction as will be more fully described andparticularly pointed out in the appended claims.

in the accompanying drawings:

FIGURE 1 is a perspective view of the propeller showing a fragmentalportion of the drive shaft and the control rod;

FIGURE 2 is a top plan view of the propeller of FIG- URE 1 with theblades located in feathering position;

FIGURE 3 is a sectional view taken in the plane of the axes of theblades looking rearwardly;

FIGURE 4 is a sectional view looking down from above on the hub withportions broken away for clarity and illustrating one of the blades asin feathering position with the blade actuating plunger at one end ofthe its stroke;

FIGURE 5 is a view similar to FIGURE 4 but illustrating the plunger asmoved to substantially the other end of its stroke and the blade shownas in reverse position, the drive shaft being of left-hand rotation;

FIGURE 6 is a perspective view of the plunger and its linkage connectionto the spindle of one of the blades; and

FIGURE 7 is a diagrammatic view illustrating the various positions ofthe lever and linkage mechanism and showing the corresponding positionof the blade with reference thereto.

In proceeding with this invention, I have provided a hub having anaxially extending cylindrical cavity in which a generally cylindricalplunger is slidably guided. A rod extends forwardly from the plunger outof the hub and through the drive shaft for actuation of the plungeraxial- 1y of the hub and drive shaft. A plurality of propeller bladesare rotatably mounted in the hub. The axes of these blades are in aplane at right angles to the axis of the hub and propeller shaft, andthe axis of each blade is offset to one side of but parallel to a radiusfrom the axis of the hub sufficiently to position the axis at one sideof the cylindrical cavity in the hub. The bearing for the spindle of theblade is formed of a size so that it intersects the cylindrical cavityof the hub, and a lever arm extending from the spindle of the bladeextends into the hub cavity and is t ere connected by means of a link tothe plunger in the cavity, thus providing a long leverage arm from theaxis of the blades for multiplying the force and distance of strokewhich is applied through the rod and plunger to rotate the blades.

The hub is circular in a plane at right angles to the shaft axis and isalso arcuate in form in a plane passing through the shaft and hub axes.The trailing edge of the blade is curved on its edge nearest the hub soas to follow the curvature of the hub and by reason of the hub beingcurved in two different planes, this blade may swing so as to followthis curvature rather closely.

With reference to the drawings, li'i designates the drive shaft from avessel. This drive shaft is hollow with a rod 11 extending therethrough.A hub 12 is secured on the outboard end of the drive shaft and iscylindrical in cross section at right angles to the axis of the driveshaft and is also arcuate as at 13 in any plane which passes through itand includes the axis of the hub. The blades designated generally 14comprise blades proper 15 and spindles 16 extending therefrom. Thesespindles are rotatably mounted in bosses 17 projecting outwardly fromthe generally curved surface of the hub 12 as can well be seen in thesection taken in FIGURE 3 extending through these bosses. The edge 13 ofeach blade is curved to follow closely the curved surface of the hub 12in a plane at right angles to the shaft axis and which will also followthe longitudinally arcuate form of the hub as shown at 13. This permitsof a wide angle range of swinging of the blade Without contacting thesurface of the hub.

Each of the bosses are bored to provide a bearing 20 for the spindle inof the blade, and this spindle is recessed as at 22 to receive an O-ring21 so as to seal this spindle in its bearing and prevent the entry ofsea water into the hub. The spindle is also recessed as at 23 so as toreceive a projection 24 from the bearing 20 so as to lock the blade inposition. The lower end 29 of the spindle 16 is received in a reducedportion 30 of the bearing. The hub is formed in three sections 25, 26and 27 (see FIGURES 4 and 5). The sections 25 and 26 separate along aplane passing through the axes of the spindles 16 for the assembly ofthe spindles in the bearings 20. These three sections are held togetherby bolts 28 passing through sections 27 and 26 and threaded into section25 as may be seen in FIGURE 2.

Extending radially from each of the blade spindles, there is a lever arm31 (see FIGURES 3, 4, 5 and 6) which is bifurcated as seen in FIGURES 3and 6. A plunger 32 is generally or pseudo cylindrical and presentssurfaces on the arc of a cylinder and is slidably guided in thecylindrical cavity 33 of the hub and keyed against rotation as at 32'.The cylindrical surface of this plunger is cut away in three locationsso as to provide essentially three rails 34 which are slotted as at 35so as to open on opposite sides, and a link 36 is located in each ofthese slots and pivotally held therein by means of a pin 37 extendingacross the slot. The other end of this link is pivoted as at 38 in thelever arm 31. The rod 11 is secured to and extends from this plunger 32,by means of which the plunger may be moved axially of the drive shaftand the hub by any convenient means, such for instance as a hydrauliccylinder or some other means of actuation.

The blades l5 are shaped somewhat so that they do not lie in a singleplane but they do extend generally in a single plane which is located atan angle to the radial projection of the lever arm 31 from the bladeaxis.

1 term the feathering position of the blades as a position in which thegeneral plane of the blades extends parallel to a plane which would passthrough the axis of the shaft and hub such as shown in FIGURE 4. This isa position in which, when the drive shaft is not rotating, the bladeswill present the least drag to being drawn through water in thedirection of the axis of the drive shaft and is a position which wouldbe assumed when a sailing vessel equipped with this propeller were beingpropelled by sail alone and without power. This position indicatessubstantially the full throw of the plunger 32 rearwardly into the hub12 or into the cap portion 27 thereof. If this plunger is drawnforwardly by the rod 11, it will be apparent that the blade 15 as seenin Pl URE 4 will be angled by its leading edge 40 moving to the left andits trailing edge 41 moving to the right as seen in FIGURE 4, which willbe the position for driving the vessel forwardly assuming a shaft to berotating left-handed or counter clockwise as shown in ElGURE 1. As theplunger is drawn further forwardly, at some point the blade v15 will bein a plane substantially at right angles to the axis of the shaft whichis referred to as a neutral position and in this position rotation ofthe shaft will not drive the vessel either forwardly or rearwardiy butthe propeller will rotate without affecting movement of the vesselforwardly or rearwardly, thus giving no drive either forwardly orrearwardly from its rotation. Further movement of the rod 11 inboard'andadvancing of the plunger 32 will cause the blade 15 to move into aposition for causing rearward motion of the vessel, and the extremerearward position of the blade is shown in FIGURE 5 e where it will benoted that the link 36 is at substantially.

right angles 'to the lever arm 31 which is the maximum position that maybe had by the angular arrangement here shown.

Referring to FIGURE 7 which is diagrammatic, several different positionsof the lever arm 3-1 and the link 36 are illustrated together with theposition of the blade 1:5. In the feathering position in thisdiagrammatic figure, a single prime is added to the designating number,thus the lever arm is designated as 31 and the link as 36'. Thecorresponding position of the blade is designated as The pivot point forthe link to the plunger is designated as 37' and the pivot point for thelink to the lever arm is designated as 38'. A second assumed position ofEEG- URE 7 shows the blade in the forward driving position about midwaybetween feather and neutral, which will be the most'used position fordriving the vessel, and in this case the numerals carry a double prime,the lever ,arm is designated as 31", the link as 36", the position ofthe blade as 15", the position of one pivot of link 36 as 37 and theposition of the pivot of the other end of this link as 3 8". A thirdposition as assumed which is that of the blade in neutral position. Herethe numerals carry a triple prime; the blade is designated as 15", thelever arm as 31", the link as 36", the pivots of this link as 37" and38". A fourth position is assumed which is that of maximum reverse inwhich the numerals carry four primes. The blade is indicated at 15, thelever arm as 31", the link as 36"" and the pivots of the link as 37""and 38".

From this diagrammatic view, it will be observed that the more importantpositions of the lever arm which is about the mid-ahead position is aposition in which the lever arm '31 or as shown in the diagrammatic view3 1 is in a position to receive an almost maximum thrust in thedirection of movement of the plunger along line 39 as the pivot 38through which force is applied is the maximum distance from the axis ofthe blade spindle in. Thus in this position of the blade which resultsin maximum hydraulic force due to axial thrust of the turning propeller,the lever arm and link are in such relation that a resistance to thisthrust is provided at the most advantageous location of the swinginglever arm, and by reason of the axis of the blade being off center fromthe line of the plunger, a long lever arm 31 or 31" as shown in thediagrammatic view is provided which is of marked advantage and amaterial improvement over the mechanical to the blades which hasheretofore been had. The offset of the axis of the blade spindle thus isa material advantage in the application of power thereto in this type ofa mechanism with the linkage operation which has been provided.

It will be readily observed that by varying the angle whichthe blade ispositioned relative to the lever arm, certain variations of thisdiagrammatic view may be had and the position of greatest advantage forthe lever arm with reference to the angle of the blade may be selectedto be about the location of most use. advantage makes for easiermovement of the blades in the astern positions, and also in the aheadpositions to a someably mounted in said hub with their axes in a planeat right angles to the axis of the hub and each blade axis being ofisetto one side of but parallel toa radius from I said hub axis, each bladecarrying within the hub a lever arm projecting from the blade axis, alink pivoted to said arm and to said plunger, said blade being generallyin a plane at an angle to the projection of said lever arm,substantially said lever arm being in a line parallel to the line ofmovement of said plunger when said blade is in reverse pitch positionand said link being at substantially right angles thereto.

2. In a controllable pitch propeller as in claim 1 wherein the stroke ofthe plunger is of suificient extent for movement of the blade from apitch position of parallel to a plane passing through the hub axis tobeyond a neutral in plane at right angles to the hub axis to a reversepitc 3. In a controllable pitch propeller as in claiml wherein the hubhas a cylindrical cavity and the plunger is a p eudo cylinder presentinga portion of a cylindrical surface slidable therein, a rod secured tosaid plunger and extending from said hub for actuation of the plunger.

4. In a controllable pitch propeller as in claim 1 wherein the hub has acylindrical cavity and the plunger is a pseudo cylinder presenting aportion of a cylindrical surface slidable therein, with slots to receivesaid links, a rod secured to said plunger and extending from said hubfor actuation of the plunger.

References Cited in the file of this patent UNITED STATES PATENTS1,656,019 Roberts Jan. 10, 1928 1,756,215 Schneider Apr. 29, 19301,816,730 Hardin July 28, 1931 2,354,465 Le Bert July 25, 1944 2,476,638Stuart July 19, 1949 FOREIGN PATENTS 393,113 Germany Mar. 29, 1924447,950 Great Britain May 28, 1936 509,417 Great Britain July 14, 1939754,852 Great Britain Aug. 15, 1956 Thus this power

1. IN A CONTROLLABLE PITCH PROPELLER, A HUB, A PLUNGER AXIALLY MOVABLEIN SAID HUB, A PLURALITY OF BLADES ROTATABLY MOUNTED IN SAID HUB WITHTHEIR AXES IN A PLANE AT RIGHT ANGLES TO THE AXIS OF THE HUB AND EACHBLADE AXIS BEING OFFSET TO ONE SIDE OF BUT PARALLEL TO A RADIUS FROMSAID HUB AXIS, EACH BLADE CARRYING WITHIN THE HUB A LEVER ARM PROJECTINGFROM THE BLADE AXIS, A LINK PIVOTED TO SAID